Tool error feedback agent not working

[mylux]

Hi @evalstate , as promised, I've tested our last PR and it seems like the solution is not working properly. Here are some evidences:

In the image below, you can see the error message in red, produced by the mcp tool, but the error_channel_messages keeps being None, what is not expected.

This image shows the value of the tool_message.channels variable:

By looking at the screenshot above, you can clearly see that the fast agent error channel was not created (it should by indexes as fast-agent-error, but there is only one mcp-ui there).

In this last screenshot, we can see the error message correctly placed in the tool_message variable, under tool_message.tool_results.call_m1j39bcx. See below:

I will try to investigate and develop a solution for that, but you will have far more context than me and will figure out the issue a lot faster.

[mylux]

The issue is very probably here. The tool call is not producing an exception, but simply a normal response with the isError attribute set as True.

[mylux]

Maybe this would do the trick?
#435